蜜枣在烘制过程中褐变相关因素分析

试验以新疆阿克苏地区不同成熟度的骏枣为试材，采用常压二次煮制渗糖工艺，55 ℃恒温烘制，以总酚、抗坏血酸含量、叶绿素含量、游离氨基酸总量、5-HMF含量等为评价指标，结合相关性分析与主成分分析方法，探究蜜枣在烘制阶段褐变情况。结果表明:不同成熟度原料的蜜枣随着烘制时间的延长，各项致褐变因子的含量变化不同。相关性分析发现三种成熟度蜜枣的色差与总酚、叶绿素等指标呈极显著正相关（P<0.01），抗坏血酸含量与5-HMF指标呈极显著负相关（P<0.01）。由主成分分析可知，成熟度、5-HMF、抗坏血酸含量等是影响蜜枣在烘制过程中褐变的主要因素。并且红枣经过（V_C 1.25 g/kg、焦性亚硫酸钠1.25 g/kg、柠檬酸3 g/kg、NaCl 25 g/kg）护色处理后与对照组相比有明显抑制褐变的作用。由此可见蜜枣的烘制阶段褐变情况是一个复杂的非酶褐变的过程，也为后续进一步研究提供了理论依据。

Correlation Analysis of Browning of Jujube During Roasting

The experiment used Junzao jujube with different maturity in Aksu area of Xinjiang as the test material, using the normal pressure twice boiling sugar infiltration process, roasting constant temperature of 55 ℃, with total phenols, ascorbic acid content(Vitamin C), chlorophyll content, total free amino acids, 5-HMF as the compratrate content, etc. It combined correlation analysis with principal component analysis to explore the browning of jujube during the roasting stage.The results showed that the content of browning factors varied with the drying time of jujube at different maturity.Correlation analysis found that the color difference of the three maturity dates was significantly positively correlated with total phenol, chlorophyll and other indexes (P<0.01), ascorbic acid content was significantly negatively correlated with 5-HMF index (P<0.01).The principal component analysis showed that maturity, 5-HMF and ascorbic acid content were the main factors affecting the browning of jujube during the roasting process.In addition, compared with the control group, jujube treated with color preserving treatment (V_C 1.25 g/kg, sodium pyrosulfite 1.25 g/kg, citric acid 3 g/kg, NaCl 25 g/kg) had a significant effect on browning inhibition.It can be seen that the browning of jujube in the baking stage is a complicated non-enzymatic browning process, which also provides a theoretical basis for further research.